Dump of list of maps produces invalid Scss code

[FlyingDR]

Attempt to dump (using @debug) a map that contains list of map as value of map entry produces invalid Scss code.

Consider this small script:

@debug (
    a: ((x:1),(y:2)),
    b: (c:1),
);

Expected output:

DEBUG: (a: ((x: 1), (y: 2)), b: (c: 1))

Actual output:

DEBUG: (a: (x: 1), (y: 2), b: (c: 1))

Notice lack of surrounding brackets around value for a key of the map.

Component versions used into test (as shown by sassc --version), of freshly compiled libsass on Ubintu:

sassc: 3.6.1-8-g3e73
libsass: 3.6.3-40-gf674
sass2scss: 1.1.1
sass: 3.5

Same output is produced by latest node-sass on Windows:

node-sass       4.13.0  (Wrapper)       [JavaScript]
libsass         3.5.4   (Sass Compiler) [C/C++]

dart-sass v1.24.1 generates correct output.